Self-harm is common, being reported in around 10% of adolescents. About 10% of those who self-harm will repeat further acts of self-harm, and self-harm, not surprisingly, is a strong predictor of subsequent suicide.1 Self-harm is commoner in female adolescents than males and about 1 in 8 of those who self-harm in the community present to hospital.1 Suicide is fortunately not common but nevertheless reported as the second or third commonest cause of adolescent death in the Western world.1 ,2 Self-harm in adolescence is thus a very significant public health problem and has been recognised as such by the publication of two related clinical guidelines by NICE (National Institute for Health and Care Excellence), (Self-harm: The short-term physical and psychological management and secondary prevention of self-harm in primary and secondary care: CG16, 2004 and Self-harm: Longer-term management: CG133, 2011).

Unfortunately, despite the importance of the problem, there are only a small number of published evaluations of interventions to prevent self-harm or its repetition.1 ,2 Slee and colleagues3 have reported that the addition of a brief cognitive behavioural therapy (CBT) intervention to treatment as usual (TAU) reduces self-harm 9 months after randomisation but the participants (aged 15–35) had a mean age of 23.9 years for TAU and 24.5 for the intervention …